Sulfonate and sulfo-carboxylate containing sodium base grease



States P e Leslie U. Franklin and Julius C. Gebhart, Port Arthur, Tex., assignors to Gulf Oil Corporation, Pittsburgh, Pa., a corporation of Pennsylvania No Drawing. Application May 31, 1955 Serial No. 512,318

4 Claims. (Cl. 25233.2)

This invention relates to a grease composition and more particularly to a grease suitable for high temperature lubrication.

Grease compositions suitable for use in wheel bearings, ball or roller bearings such as those used in paper mills, cement mills, steel mills, etc., should possess good mechanical and chemical characteristics at the elevated temperatures and pressures often encountered in such applications. Among the mechanical and chemical characteristics desirable in such compositions are included a high ASTM dropping point, good bearing retention, resistance to failure under load, resistance to oxidation, a smooth appearance and a buttery texture.

While grease compositions prepared from sodium base soaps have a majority of the properties designated above, some difiiculty is encountered in obtaining a sodium base soap grease having all of the above properties. The characteristics of greases prepared from sodium soaps can be altered to some extent by adjusting the alkalinity of the grease. For example, we have found that a sodium soap grease which is slightly acidic is soft and plastic. As the free alkali content of the grease is increased, the dropping point and flow point of the grease is also increased. To further illustrate the efiect of alkalinity, attention is directed to conventional sodium tallow greases. The sodium tallow greases are generally fibrous by nature, often to the extent of being ropy (long fiber) which is objectionable to the bearing grease trade because of the tendency of the grease to be thrown out of the hearing or to heat excessively in a running bearing due to improper channeling. Wehave found that the length of the fiber and consequently the texture of the sodium tallow greases can be satisfactorily controlled by adjusting the alkalinity of such greases.

A disadvantage accompanying increased alkalinity in sodium base soap greases and sodium tallow greases is the deleterious effect on the stability of such greases. For example, as the alkali content of sodium base soap greases is increased the hot dry soap base becomes more rubber-like and harder until it crumbles or breaks because of the separation of the hard soap and oil. Likewise, in the case of the sodium tallow greases an excess of alkali gives rise to separation of the oil and soap.

We have discovered that a sodium grease composition having a smooth appearance and improved dropping point containing up to about 2 percent by weight free alkalinity as sodium hydroxide can be prepared by dispersing a small amount of each of a metal salt of an oil-soluble petroleum sulfonic acid, a metal salt of a s-ulfo-carboxylic acid, and a sodium soap in a major amount of a mineral oil.

Patented June 2 1959 The mineral oil ingredient in the composition provided by this invention may be any of the hydrocarbon oils of lubricating grade customarily used in compounding greases. The oil may be a refined or semi-refined paraffinic-, naphthenic-, or asphaltic-base oil having a viscosity of about 50 to about 4000 SUS at 100 F. If desired, a blend of oils of suitable viscosity may be employed instead of a single oil, by means of which any desired viscosity within the range of 50 to 4.000 SUS at 100 F., may be secured. The viscosity of the oil-has little effect on the dropping point of the compositions but more viscous oils produce compositions having greater stickiness and adhesive properties than do the lighter oils. The oil content of the compositions prepared according to this invention can comprise about 60 to about percent by weight of the total composition. The particular oil as well as the exact amount of oil depends upon the characteristics desired in the final composition.

The sodium soap which can be employed in the composition of the invention can be prepared from-fats such as tallow or from fatty acids. The fatty acids employed are substantially saturated, higher, unsubstituted aliphatic acids, and include acids such as lauric, myristic, palmitic, stearic, arachidic, behenic, and the like. The sodium compounds are truesoaps'or salts which are formed by the replacement of the hydrogen atom of the carboxyl group or groups of the acid. We can use the sodium soap of either substantiallypure fatty acids or mixtures of fatty acids such as those obtained from the various fatty oils, such as cottonseed oil, rapeseed oil, animal oils, fish oils, and the like. The saturated fatty acids such as those obtained from hydrogenated oils' of vegetable, animal, and marine extraction can also be used. For example, we can use the sodium soap of the fatty acids obtained by the hydrogenation of a vegetable oil, such as castor oil, or a fish oil, such as sardine oil, herring oil, cod oil, menhaden oil, andthe like. The hydrogenation of these oils isnot a part of this invention but may be carried out'by various known procedures such, for example, as the process described on pages 372 to 430 of Hydrogenation of Organic Substances, third edition, by Carleton Ellis, D. Van Nostrand Co., Inc., New York (1930) Since the use of a pure fatty acid is generally too expensive to employ in preparing a soap for makinga grease, it is preferred to employ commercially available mixtures of predominantly saturated fatty acids such as are obtainable, for example, inhydrogenated fish oil fatty acids. These acids represent distilled cuts of mixtures of fatty acids containing, variable amounts of C to C acids. We have found that a grease of theinvention prepared from the sodium soap of a mixture of G to C fatty acids containing about 50 percent by weight, or more, of acids having at least 20 carbon atoms has excellent mechanical stability.

A series of commercially available organic fatty acids derived from hydrogenated animal, vegetable, and marine oils suitable for use in the prepanation of soaps appear in the trade, among which are Hydrofol Acids, marketed by Archer-Daniels-Midland Col, Chemical Products Division, Cleveland, Ohio, and"Hyfac Fatty Aci marketed by Emery Industries, Inc., Cincinnati, Ohio. Of theHydrofol Acids, Hydrofol A43 Acids? are particularly advantageous in preparing a composition of the invention because of the presence: of relatively 3- large amount of C and C fatty acids. The percentage composition of some of the commercially available hydrogenated fatty acids which we can use in making the sodium soap is shown in Table 1.

Table 1 Straight Chain Hyi'ac Hydro- Hydro- Hydro- Hydro- Fatty Acids, No. 410 01 fol fol (01 of OarbonAtoms A-B 150 51 405 14 3 1. 8 7. 5 1. 5 16.- 30 13. 5 10. 33. 3 28. 0 18-- 66 17. 2 90. 0 27. 2 70. 20-- 38. 3 17. 2 22.- 29. 2 14. 8 Unsaturated 5 2. 3 3. 2 4. 3 6. 0 Miscellaneous 1 The amount of the sodium soap employed should be suflicient to thicken the oil to the consistency of a grease. For greases of the type employed in the lubrication of anti-friction bearings, the sodium soap content of the grease comprises about 5 to about 40 percent by weight of the grease composition.

The metal salt of an oil-soluble petroleum sulfonic acid and the metal salt of a sulfo-carboxylic acid are advantageously prepared by sulfonating a mixture of mineral and fatty oils, the sulfonated product being extracted from the reaction mixture and converted to their respective metal salts. As discussed more fully hereinafter, these salts need not be prepared simultaneously.

The treatment of a mineral oil with sulfuric acid such as, for example, the acid refining of petroleum distillates produces sulfonic acids commonly referred to as mahogany aci and green acids. The mahogany acids are the oil-soluble sulfonic acids whereas the green aci are the water-soluble derivatives. There are two general methods employed in recovering the mahogany acids. The first method involves selectively removing the acids by adsorbents or by solvents such-as the lower mono-basic alcohols. The second method involves salting out the acids with inorganic salts or bases. These methods are well known and have been described in detail by Carleton Ellis on page 1070 of volume 2 of The Chemistry of Petroleum Derivatives, Reinhold Publishing Corporation, New York, 1937 (second printing 1945). The sodium salt of an oil-soluble petroleum sulfonic acid obtained by the salting out procedure is an example of a material suitable for use in this invention. Particularly suitable petroleum sulfonates are those having a molecular weight of about 300 to about 600.

' The action of sulfuric acid on fatty acids and their derivatives has been the subject of many investigations and the basis of numerous patents pertaining not only to sulfonating agents and methods of sulfonating but also to means of purifying the reaction products obtained. For instance, the reaction of sulfuric acid with castor oil to produce Turkey-red oil, an emulsifying agent, is well known in the prior art. However, what occurs during sulfonation of the fatty acids has resulted in considerable prognostication. While it is generally considered that only the unsaturated fatty acids can be sulfonated, the formation of additional products between the saturated acids and sulfuric acid has been postulated. In some instances, sulfonation and condensation reactions are reported to occur simultaneously, a classic example of which is the preparation of the so-called Twitchell reagents, obtained by sulfonating mixtures of unsaturated acids and aromatic hydrocarbons. The original "Iwitchell reagent consisted of the reaction product of benzene, oleic acid and concentrated sulfuric acid. The product was designated by Twitchell, in the Journal of 4 I the American Chemical Society, volume 22, page 22 (1900), as benzenestearosulfonic acid,

C H4( a C18H3502 While we do not wish to be limited with respect to theory, we believe that treating a mixture of mineral and fatty oils with sulfuric acid results in sulfonating some of the mineral oil components and condensing some of the aromatic constituents of the mineral oil with the fatty acid of the fatty oil while simultaneously sulfonating the fatty acid. Formation of the metal salt of the sulfofatty acid occurs when forming the salt of the oilsoluble petroleum sulfonic acid. In any event the salted out product which we can employ has been determined by chemical analysis to comprise a mineral oil concentrate of sodium petroleum sulfonate and sodium sulfocarboxylate the weight ratio of petroleum sulfonate to sulfo-carboxylate being about 8 to 1.

While we have described a method whereby a metal salt of a petroleum sulfonic acid and a metal salt of a carboxylic acid are simultaneously obtained, it will be understood that these salts can be separately prepared. In any event, whether prepared simultaneously with the petroleum sulfonate or by itself, the sulfo-carboxylate is advantageously the product resulting from the sulfonation of a long, straight chain, unsaturated fatty acid containing about 12 to about 22 carbon atoms. The sulfur content of suitable sulfo-carboxylatcs comprises about 0.5 to about 3.0 percent by weight based on the weight of the metal sulfo-carboxylate.

While we can add the metal salt of the oil-soluble petroleum sulfonic acid and the metal salt of the sulfocarboxylic acid either separately or in mixtures thereof, we prefer to add a mixture of these salts in the form of a mineral oil concentrate in order to facilitate the preparation of a homogeneous composition. When a mineral oil concentrate of these salts is employed, the mineral oil may comprise about 5 to about 50 percent by weight of the concentrate. An example of a commercially available mineral oil concentrate comprising a mixture of the sodium salt of the oil-soluble petroleum sulfonic acids and the sodium salt of a sulfo-carboxylic acid particularly suitable for use in the composition of the invention is Twitchell 8266 Base marketed by Emery Industries, Inc., Cincinnati, Ohio.

Since the grease composition of this invention is directed primarily to a sodium soap grease, we advantageously employ the sodium salt of an oil-soluble petroleum sulfonic acid and the sodium salt of a sulfocarboxylic acid. However, other metals selected from the group consisting of calcium, barium and lithium can be used in forming a salt for the purpose of this invention.

In preparing the grease composition of this invention We employ about 0.5 to about 5.0 percent by weight of a metal salt of an oil-soluble petroleum sulfonic acid and at least about 0.1 percent by weight of a metal salt of a sulfo-carboxylic acid. If less than about 0.1 percent by weight of the sulfo-carboxylate is used, the resulting composition has less than all of the improved character istics. We prefer, therefore, to use between about 0.1 and about 1.0 percent by weight of the sulfo-carboxylate. When a mineral oil concentrate of the petroleum sulfonate and the sulfo-carboxylate is employed the metal salt portion of the concentrate can comprise about 80 to about percent by weight of a metal salt of an oilsoluble petroleum sulfonic acid and about 5 to about 20 percent by weight of a metal salt of a sulfo-carboxylic acid.

In instances where the grease composition of our invention is subjected to prolonged use under oxidizing conditions, we advantageously incorporate in the grease a small amount of an oxidation inhibitor such as, for

fag 389,286

example, a diaryl amine. Examples of some of the diaryl amines which can be used in the composition of our invention may be mentioned, diphenylamine, phenyl alpha naphthylamine, phenyl beta naphthylamine, alpha alpha-, alpha beta-, and beta beta-dinaphthylarnines, and the like. The amount of the diaryl amine employed will depend to a large extent uponthe severity of the conditions to which the grease is subjected, as well as the tive can be added. Upon further cooling to about 130 to about 140 F., the grease can be further blended with additional oil and further quantities of conventional additives to give a grease having the desired soap content.

particular diaryl amine used. Generally, however the amount of the diaryl amine employed is between about 0.1 and 1.5 percent by Weight based upon the weight of the total composition. additives including rust inhibitors, extreme pressure agents, tackiness modifiers, corrosion-inhibitors, oiliness agents, dyes, and the like can be added to the. composition of our invention without departing from the scope thereof. For example, we can add cocoammonium isoamyl isooctyl orthophosphate to the composition tov impart excellent corrosion resistance of this grease to steel.

In preparing the composition of the present invention, yxarious methods may be used in compounding and blending the lubricating oil with the other specified ingredients. The sodium soap may be prepared and then added to the oil, or the soap may be prepared in situ. According to one embodiment when making a tallow grease, all of the tallow, hydrogenated fatty acids, flake sodium hydroxide, the metal salt of an oil-soluble petroleum sulfonic acid, the metal salt of a sulfo-carboxylic acid and water are charged to a conventional saponification kettle together with about 20 to about 30 percent of the mineral oil base to give about a 40 to 50 percent soap base grease. Saponification is carried out at a pressure of about 40 to about 60 pounds per square inch gauge at a temperature of about 400 to about 410 F. for a period of time suflicient to effect saponification. The kettle containing the saponified mass is then vented to release the pressure after which heating at 400 to 410 F. is continued to eifect dehydration. After dehydration, the dehydrated mass is discharge to a kettle wherein the mass is cooled to about 300 to about 325 F. While maintaining the mass at a temperature of about 300 to about 325 F. an additional portion of the mineral oil is slowly added to produce about a 20 to 30 percent soap base grease. While further cooling the mass to a temperature of about 240 to about 250 F. the

If desired, other conventional remainder of the oil is added to give a grease having the desired soap content. If an oxidation inhibitor, corrosion inhibitor or other conventional additive is employed, it is advantageously added with stirring when the grease is further cooled to about 170 to about 180 F. Depending upon the properties desired in the final product, the grease may or may not be subjected to conventional milling.

According to another embodiment where no tallow is employed, all of the hydrogenated fatty acids, flake sodium hydroxide and water and about one half each of the metal salt of an oil-soluble petroleum sulfonic acid and of the metal salt of a sulfo-carboxylic acid are charged to a conventional 'saponification kettle together with suflicient oil to give a grease whose soap content comprises about 40 to about percent by weight of the composition. Saponification is eifected at a pressure of about 30 to about 50 pounds per square inch gauge at a temperature of about 300 to about 330 F. The saponified mass is then discharged to a second kettle where dehydration is effected at about 300 to about 330 F. The dehydrated mass is then cooled to about 210 to about 220 F. at which time the other half of the metal salt of an oil-soluble petroleum sulfonic acid and metal salt of a sulfo-carboxylic acid and additional oil are added to produce a grease having about a 25 percent soap con tent. Cooling nad stirring are continued until a temperature of about 180 F. is reached at which time the antioxidant and rust inhibitor-or other conventional addi- The grease thus obtained can be milled if desired. While the metal salts of the oil-soluble petroleum sulfonic acid and sulfo-carboxylic acid are advantageously added in the high-temperature stages of the grease-making procedure, these salts can be added during the cooling and finishing stages. When added to the finished grease, however, it is essential that the salt be substantially anhydrous.

In order to illustrate our invention more particularly, comparative grease compositions were made according to the compounding procedure set forth hereinabove. Compositions A, D, E, F and G were made according to the procedure described in the first illustrative embodiment. Compositions B, C, H and I were prepared according to the procedure described in the second illustrative embodiment. The improved properties of a composition of the invention will be apparent from the data shown in Table 4. The mineral oil used in the make-up of compositions A, D, E, F and G comprised about 75 percent by weight of a mineral oil having a viscosity of about 200 SUS at 100 F., and about 25 percent by Weight of a mineral oil having a viscosity of about 1300 SUS at 100 F. The mineral oil used in compositions B, C, H and I shown in the table comprised about percent by weight of a mineral oil having a viscosity of about 375 SUS at F., and about 15 percent by weight of a mineral oil having a viscosity of about SUS at 100 F. The blend obtained in each instance had a viscosity of about 300 SUS at 100 F.

The mineral oil concentrate used in preparing composition E was obtained from Sherwood Refining Co., Englewood, New Jersey. This concentrate designated as Sherosope T contained an extremely small amount of sulfo-carboxylate. The metal salt portion of this concentrate comprised about 0.5 percent by weight sodium sulfo-carboxylate and about 99.5 percent by weight sodium petroleum sulfonate. The mineral oil concentrate of petroleum sulfonate and sulfo-carboxylate employed in preparing compositions F, G, H and I was a commercially available concentrate designated as Twitchell 8266 Base marked by Emery Industries, Inc., Cincinnati, Ohio. The metal salt portion of this concentrate comprised about 10.9 percent by weight sodium sulfo-carboxylate and about 89.1 percent by weight sodium petroleum sulfonate. Typical properties and make-up of these concentrates are shown in Table 2 as follows.

Table 2 Twitchell .Sherosope 8266 Base T Composition, Percent By Weight:

Mineral oil 38. 2 32.0 Sodium sulfo-carboxylate 5. 8 0. 3 Sodium sulfonate 47. 4 65.0 Inorganic salts trace 0.6 ater 5. 6 2.0 Inspection:

Gravity, API 7. 3 7. 5 Viscosity, SUS- at 100 F 7. 388 at 210 290 1, 373 Sulfur, percent 3. 23 4. 03 Water by dist ation, percent by wt.,

ASTM D 95-46 5. 6 2.0 Carbon residue, Gonradson, percent,

ASTM D 189-52 14. 5 10. 4 Neutralization value, ASTM D 974-53T,

Total acid number 1. 6 nil Saponification No., ASTM D 94-521 2. 6 0. 1

The properties of the mineral oil, sodium sulfonate and separated sulfo-carboxylic acids of the concentrate used in. compositions E, F, G,.H and I are shownin Table 3 as follows.- a a I a 1 Menzies-Wright.

The improved properties of a grease composition of the invention containing at least about 0.1 percent by weight of the sodium salt of a sulio-carboxylic acid are apparent from the data presented in Table 4. It will be noted that compositions A, B, C, D and E, for one reason or another, do not contain the desirable characteristics of a grease. Composition A is made up of long fibers and loses about percent of its oil when subjected to the bleeding test. Compositions B, C and D have an improved texture resulting from the excess sodium hydroxide. These compositions, however, were too lumpy to obtain either a dropping point or a flow point. Compositions B, C, and D were characterized by numerous soap lumps floating in the oil. These lumps were only partially dispersed when milled. Such a result is considered to be a complete failure when making a grease. By comparing composition E containing 0.01 percent by weight of the sodium salt of a sulfo-carboxylic acid with composition A which contained no such salt, it will be noted that composition E had an improved dropping point and fiow point but that the amount of oil separated was still in the order of about 10 percent. When the sodium sulfo-carboxylate content of the grease was increased to 0.1 percent by weight, a grease composition having overall improved properties was obtained as evidenced by the Table 4 Table 3 Separated Mineral Oil Sodium Sulfonate Sulfa-Car- Compesitions A boxylic Acids F, G, 11,1 E F,G,H,I E F, G, H,I

Gravity, API 29. 1 28. 3 Specific gravity, 60l60 0. 8811 0. 8855 1. 0222 1. 1073 1. 1539 Viscosity, SUS:

at 100 F- 123 7 182.9

85 91 +25 +10 Refractive Index lip 1. 48475 1 48365 1. 50211 Sulfur, B Percent- 0.. 25 0.28 6. 18 6. 13 1.08 Carbon Residue, Conradson Percent, ASTM D 189-52 0. 16 0.48 Neutralization Value, ASTM D 974-53'1, Total Acid No-- 0. 93 2. 13. 6 1.80 177 Saponification No., ASTM D 94- 521 1. 2 16. 1 3. 2 179 Average Molecular Weight 1 321 1 371 i 527 1 513 1 323 data with respect to composition F. Compositions hav.- ing improved overall properties were also obtained when the sulio-carboxylate content of the compositions was 0.16 and 0.39 for compositions G and H, respectively. It will be noted from the bleeding test for composition I that an exceedingly small amount of oil separated. The dropping point of composition 1, however, was deleteriously affected probably because of the free fatty acid present in the composition. Notwithstanding the presence of the free fatty acid the bleeding property and the appearance and texture of the grease was improved over similar greases containing a small amount of free fatty acid. It will be further noted that compositions H and I prepared from the sodium soap of a mixture of C to C fatty acids containing a total of about 50 percent C and C acids have excellent mechanical stability. The mechanical stability of a grease is evidenced by comparing its penetration value after being Worked for strokes with its penetration value after being worked for 10,000 strokes. Little or no change in penetration is in dicative of a grease having excellent mechanical stability. In this regard, it will be noted that the penetration of composition H at 60 strokes was 277 and that at 10,000 strokes it increased only to 283. While not shown in the table, further working of composition H to 100,000

Grease Composition: Percent By Weight A B Mineral Oil, 300 SUS F Sodium soap of tallow 1 Sodium soap of Hyiac 410-.-. Sodium soap oi Hydrol'ol A-B Sodium soap of Hydrofol 51 Mineral oil concentrate of petroleum sulionate and sulfo-carboxy te Mineral Oil:

124 SUS 100 F.

Diphenylamlne Phenyl alpha naphthylamine Coeoammomum isosmyl isooetyl ortho (84% concentrate in light mineral oil) Excess NaOFi Characteristics:

Dropping point, F.ASTM D 566-42 Flow point, F.Guli 58 Penetration ASTM D 2l752, '77 F., G., 5 Sec.

Unworked, Transferred Unworked Worked, 60 strokes..-

Worked, 10,000 strokes 314 28 26 Appearance d smooth.. smooth" smooth fiber lumpy lumpy. lumpy. Texture butterybuttery. short medium short short buttery. buttery fiber fiber fiber fiber.

Free fatty acid as oleic, Percent 0.08--. 0.84 0.49.

Free alkalinity as NaOH, Percent.-. 0 22 0 25"--. 0 53 0.44... 0 33...; 0 24"-..

Bleeding test, Fed. 321, 212 F., 50 hr. Separated oil, Percent 9.91--."

1 Includes glyeerine;

strokes increased its penetration value only to 302. Composition I possessed excellent mechanical stability as indicated by substantially no change in its penetration value, the values being 270 and 267 at 60 and 10,000 strokes, respectively.

We are primarily concerned with improving the properties of a highly alkaline soap base grease. However, the above data demonstrate that some beneficial results can be obtained when a small amount of a mineral oil concentrate of a sodium petroleum sulfonate and a sodium sulfo-carboxylate is added to a grease which contains free fatty acid as oleic acid.

While our invention is described above with reference to the various specific examples and embodiments it will be understood that the invention is not limited to such examples and embodiments and may be variously practiced within the scope of the claims hereinafter made.

We claim:

1. A grease composition comprising a dispersion of about 0.5 to about 5.0 percent by weight of a metal salt of an oil-soluble petroleum sulfonic acid, about 0.1 to about 1.0 percent by weight of a metal salt of a sulfonated monocarboxylic acid having about :12 to about 22 carbon atoms and a sulfur content of about 0.5 to about 3.0 percent by weight based on the weight of said metal salt of the sulfonated monocarboxylic acid, and a sodium soap of a fatty acid having about 12 to about 22 carbon atoms in an amount sufiicient to produce a composition having the consistency of a grease in a major amount of a mineral oil.

2. A grease composition comprising a dispersion of about 0.5 to about 5.0 percent by weight of the sodium salt of an oil-soluble petroleum sulfonic acid, about 0.1 to about 1.0 percent by weight of the sodium salt of a sulfonated monocarboxylic acid having about 12 to about 22 carbon atoms and a sulfur content of about 0.5 to about 3.0 percent by weight based on the weight of said sodium salt of the sulfonated monocarboxylic acid, and a sodium soap of a fatty acid having about 12 to about 22 carbon atoms in an amount suflicient to produce a 10 composition having the consistency of a grease in a major amount of a mineral oil.

3. A grease composition comprising a dispersion of about 0.5 to about 5.0 percent by weight of the sodium salt of an oil-soluble petroleum sulfonic acid, about 0.1 to about 1.0 percent by Weight of the sodium salt of a sulfonated monocarboxylic acid having about 12 to about 22 carbon atoms and a sulfur content of about 0.5 to about 3.0 percent by weight based on the weight of said sodium salt of the sulfonated monocarboxylic acid, and about 5 to about percent by weight of a sodium soap of a fatty acid having about 12 to about 22 carbon atoms in a major amount of a mineral oil.

4. An improved sodium soap grease composition containing up to about 2 percent free alkalinity as sodium hydroxide comprising a mineral oil thickened to a grease with a sodium soap of a fatty acid having about 12 to about 22 carbon atoms and containing dispersed therein about 0.5 to about 5.0 percent by weight of the sodium salt of an oil-soluble petroleum sulfonic acid and about 0.1 to about 1.0 percent by weight of the sodium salt of a sulfonated monocarboxylic acid having about :12 to about :22 carbon atoms and a sulfur content of about 0.5 to about 3.0 percent by weight based on the weight of said sodium salt of the sulfonated monocarboxylic acid, the weight ratio of the sodium salt of the oil-soluble petroleum sulfonic acid to the sodium salt of the sulfonated monocarboxylic acid being about 8 to 1.

References Cited in the file of this patent UNITED STATES PATENTS Re. 23,082 Zimmer et al. Jan. 25, 1949 2,352,811 Swenson July 4, 1944 2,394,790 Liehe Feb. 12, 1946 2,444,970 Zimmer et al July 13, 1948 2,540,534 Kolfenbach et a1. Feb. '6, 1

FOREIGN PATENTS 588,684 Great Britain May :30, 1947 

1. A GREASE COMPOSITION COMPRISING A DISPERSION OF ABOUT 0.5 TO ABOUT 5.0 PERCENT BY WEIGHT OF A METAL SALT OF AN OIL-SOLUBLE PETROLEUM SULFONIC ACID, ABOUT 0.1 TO ABOUT 1.0 PERCENT BY WEIGHT OF A METAL SALT OF A SULFONATED MONOCARBOXYLIC ACID HAVING ABOUT 12 TO ABOUT 22 CARBON ATOMS AND A SULFUR CONTENT OF ABOUT 0.5 TO ABOUT 3.0 PERCENT BY WEIGHT BASED ON THE WEIGHT OF SAID METAL SALT OF THE SULFONATED MONOCARBOXYLIC ACID, AND A SODIUM SOAP OF A FATTY ACID HAVING ABOUT 12 TO ABOUT 22 CARBON ATOMS IN AN AMOUNT SUFFICIENT TO PRODUCE A COMPOSITION HAVING THE CONSISTENCY OF A GREASE IN A MAJOR AMOUNT OF A MINERAL OIL. 